Be an active part of your health care. Know your medical history. Carry a list of your major health problems and medications and their doses with you at all times. Consider getting a medical alert bracelet.
Just because something is "in the chart" doesn't mean that I have it in my records, especially if I'm meeting you for the first time. I do not rely on "the chart" for what doses of medications you take -- you are the keeper of the pill bottles and you are the one who puts the pills in your mouth, so you are the one who knows exactly what and how much you take. Further, all of your records may not have come to me yet if I am meeting you for the first time.
And, finally, imagine this scenario: You end up sick in an emergency room where none of your doctors practice. Your medical information is absolutely crucial to your treatment in the next few minutes and hours.